The objective of grant P51-OD011133 to Texas Biomedical Research Institute is to continue support of the infrastructure of the Southwest National Primate Research Center (SNPRC). This base grant enables the SNPRC to be responsive to national biomedical research needs and to accommodate investigators who want to access Center resources for collaborative research purposes. The Southwest National Primate Research Center has an active and growing program to develop and supply the common marmoset (Callithrix jacchus) as a biomedical research resource. We propose to further enhance this SNPRC resource through the inclusion of a segment of the marmoset colony from the New England Primate Research Center. This addition will provide SNPRC with two genetically distinct colonies of marmosets that can be utilized for infectious disease, metabolic disease, aging and regenerative medicine research. This revised proposal requests support for this activity. The overall aims of the marmoset colony in the last competitive renewal were to: (1) continue production of marmosets for use in biomedical research; (2) further consortium arrangements with Wisconsin NPRC, New England PRC and the NIH Intra-mural program. Two specific goals within this aim are to have a defined, accepted profile of a marmoset diet and a SNP panel that can be used as a tool to define best animal use and animal breeding; (3) continue comparison of the SPF, barrier-maintained marmoset colony with the conventionally housed colonies, in order to identify those aspects of research use (e.g., healthy longevity) which will specifically benefit from this SPF, barrier approach to colony management and animal production. The following revised additional aims are proposed with the addition of the NEPRC marmosets to the SNPRC: (1) continue production of marmosets for use in biomedical research with the NEPRC marmosets contributing to that continued production. The NEPRC marmosets will be maintained as a separate population (hereafter referred to as Colony 2), with husbandry and diet maintained as closely as possible to the original NEPRC protocols. The increased size of the total colony will greatly enhance our ability to meet the needs of NIHfunded investigators, some of which used the marmoset model at NEPRC; (2) conduct planned comparisons of factors that represent important sources underlying phenotypic variation within and among marmoset populations. These comparisons will provide a means to identify best practices as regards to husbandry and best methods for assigning subjects to studies or breeding in relation to genetic variation. This aim will be conducted in collaboration with the Wisconsin NPRC; (3) establish a specific resource of geriatric marmosets to be used in studies of aging and chronic disease.